The internal combustion engine powering the vast majority of today's automobiles, power boats and lawn mowers has several drawbacks: the cost of fuel, the inconvenience of refueling, the depletion of a finite energy source, and the environmental impact of extracting, transporting, and burning billions of barrels of petroleum every year. There has thus been a long standing effort to develop alternative automotive energy sources. Utilizing electrical energy is the most obvious alternative, but this approach has required the use of batteries that possess their own significant drawbacks, such as: a much smaller energy density relative to gasoline, high cost of manufacture, long recharging times, short lifespans, and compromised performance in extreme temperatures. The enclosed invention depends on electricity as the ultimate source of energy but stores that energy in a fundamentally different way. Rather than relying on electrochemical batteries, the electrical energy is converted into and stored as thermal energy within an insulated reservoir. This thermal reservoir serves essentially as a replacement for the boiler in a steam driven vehicle. Without the boiler, there is no longer the need to vent combusted gas products and thus the greatest source of inefficiency in automotive steam engines is obviated. Furthermore, since the heat is already present within the thermal reservoir, there is no longer a need to ignite a lamp within a boiler and wait for steam pressure to build up; the steam can be generated almost instantly.
The thermal reservoir can be categorized as an encapsulated thermal battery. Encapsulated thermal battery technologies have mostly been directed towards regulating the operating temperature of specific components within various mechanical and electrical devices. The use of encapsulated heat as a means of energy storage has received far less attention and efforts in this regard have been generally limited to home heating or providing a means for power stations to store energy during non-peak hours. Examples of power station technology include: U.S. Pat. No. 4,146,057 that teaches the use of aluminum as a heat storage means when the primary source of energy is solar and the heat is to be later retrieved in the form of electricity; JP2000097498 teaches a heat battery employing magnesia, magnetite, silica and/or alumina as heat storage substances; and JP2007032866 teaches the importance of heat exchanger design, employing the use of fins emanating from the heat exchanger tube, when a heat battery is used for electricity generation.
Efforts at using encapsulated thermal batteries for powering vehicles have not yet been fully developed. U.S. Pat. No. 7,933,506 teaches the use of aluminum to serve as the primary thermal storage substance in the powering of vehicles. In conjunction with a robust insulating jacket, heat exchanger, and an automatic means of switching between the steam port and an insulation plug, this design offers significant energy storage potential. 500 kg of aluminum between the temperature range 150-800 C holds 549 MJ. This is the energy equivalent of 4.2 gallons of fully combusted gasoline. However, in order to achieve practical levels of stored thermal energy, the aluminum must be heated above it melting point of 657 C. In fact, 200 of the 549 MJ is attributable to aluminum's very substantial heat of fusion. Unfortunately, the combination of high temperature, high thermal conductivity, and liquid phase makes aluminum a significant hazard in the event of a collision. A robust containment means would have to be devised in order to prevent the spillage of molten aluminum.